1 /* 2 * linux/include/linux/nfs_page.h 3 * 4 * Copyright (C) 2000 Trond Myklebust 5 * 6 * NFS page cache wrapper. 7 */ 8 9 #ifndef _LINUX_NFS_PAGE_H 10 #define _LINUX_NFS_PAGE_H 11 12 13 #include <linux/list.h> 14 #include <linux/pagemap.h> 15 #include <linux/wait.h> 16 #include <linux/sunrpc/auth.h> 17 #include <linux/nfs_xdr.h> 18 19 #include <linux/kref.h> 20 21 /* 22 * Valid flags for a dirty buffer 23 */ 24 enum { 25 PG_BUSY = 0, /* nfs_{un}lock_request */ 26 PG_MAPPED, /* page private set for buffered io */ 27 PG_CLEAN, /* write succeeded */ 28 PG_COMMIT_TO_DS, /* used by pnfs layouts */ 29 PG_INODE_REF, /* extra ref held by inode when in writeback */ 30 PG_HEADLOCK, /* page group lock of wb_head */ 31 PG_TEARDOWN, /* page group sync for destroy */ 32 PG_UNLOCKPAGE, /* page group sync bit in read path */ 33 PG_UPTODATE, /* page group sync bit in read path */ 34 PG_WB_END, /* page group sync bit in write path */ 35 PG_REMOVE, /* page group sync bit in write path */ 36 }; 37 38 struct nfs_inode; 39 struct nfs_page { 40 struct list_head wb_list; /* Defines state of page: */ 41 struct page *wb_page; /* page to read in/write out */ 42 struct nfs_open_context *wb_context; /* File state context info */ 43 struct nfs_lock_context *wb_lock_context; /* lock context info */ 44 pgoff_t wb_index; /* Offset >> PAGE_CACHE_SHIFT */ 45 unsigned int wb_offset, /* Offset & ~PAGE_CACHE_MASK */ 46 wb_pgbase, /* Start of page data */ 47 wb_bytes; /* Length of request */ 48 struct kref wb_kref; /* reference count */ 49 unsigned long wb_flags; 50 struct nfs_write_verifier wb_verf; /* Commit cookie */ 51 struct nfs_page *wb_this_page; /* list of reqs for this page */ 52 struct nfs_page *wb_head; /* head pointer for req list */ 53 }; 54 55 struct nfs_pageio_descriptor; 56 struct nfs_pageio_ops { 57 void (*pg_init)(struct nfs_pageio_descriptor *, struct nfs_page *); 58 size_t (*pg_test)(struct nfs_pageio_descriptor *, struct nfs_page *, 59 struct nfs_page *); 60 int (*pg_doio)(struct nfs_pageio_descriptor *); 61 unsigned int (*pg_get_mirror_count)(struct nfs_pageio_descriptor *, 62 struct nfs_page *); 63 void (*pg_cleanup)(struct nfs_pageio_descriptor *); 64 }; 65 66 struct nfs_rw_ops { 67 const fmode_t rw_mode; 68 struct nfs_pgio_header *(*rw_alloc_header)(void); 69 void (*rw_free_header)(struct nfs_pgio_header *); 70 int (*rw_done)(struct rpc_task *, struct nfs_pgio_header *, 71 struct inode *); 72 void (*rw_result)(struct rpc_task *, struct nfs_pgio_header *); 73 void (*rw_initiate)(struct nfs_pgio_header *, struct rpc_message *, 74 const struct nfs_rpc_ops *, 75 struct rpc_task_setup *, int); 76 }; 77 78 struct nfs_pgio_mirror { 79 struct list_head pg_list; 80 unsigned long pg_bytes_written; 81 size_t pg_count; 82 size_t pg_bsize; 83 unsigned int pg_base; 84 unsigned char pg_recoalesce : 1; 85 }; 86 87 struct nfs_pageio_descriptor { 88 unsigned char pg_moreio : 1; 89 struct inode *pg_inode; 90 const struct nfs_pageio_ops *pg_ops; 91 const struct nfs_rw_ops *pg_rw_ops; 92 int pg_ioflags; 93 int pg_error; 94 const struct rpc_call_ops *pg_rpc_callops; 95 const struct nfs_pgio_completion_ops *pg_completion_ops; 96 struct pnfs_layout_segment *pg_lseg; 97 struct nfs_direct_req *pg_dreq; 98 void *pg_layout_private; 99 unsigned int pg_bsize; /* default bsize for mirrors */ 100 101 u32 pg_mirror_count; 102 struct nfs_pgio_mirror *pg_mirrors; 103 struct nfs_pgio_mirror pg_mirrors_static[1]; 104 struct nfs_pgio_mirror *pg_mirrors_dynamic; 105 u32 pg_mirror_idx; /* current mirror */ 106 }; 107 108 /* arbitrarily selected limit to number of mirrors */ 109 #define NFS_PAGEIO_DESCRIPTOR_MIRROR_MAX 16 110 111 #define NFS_WBACK_BUSY(req) (test_bit(PG_BUSY,&(req)->wb_flags)) 112 113 extern struct nfs_page *nfs_create_request(struct nfs_open_context *ctx, 114 struct page *page, 115 struct nfs_page *last, 116 unsigned int offset, 117 unsigned int count); 118 extern void nfs_release_request(struct nfs_page *); 119 120 121 extern void nfs_pageio_init(struct nfs_pageio_descriptor *desc, 122 struct inode *inode, 123 const struct nfs_pageio_ops *pg_ops, 124 const struct nfs_pgio_completion_ops *compl_ops, 125 const struct nfs_rw_ops *rw_ops, 126 size_t bsize, 127 int how); 128 extern int nfs_pageio_add_request(struct nfs_pageio_descriptor *, 129 struct nfs_page *); 130 extern int nfs_pageio_resend(struct nfs_pageio_descriptor *, 131 struct nfs_pgio_header *); 132 extern void nfs_pageio_complete(struct nfs_pageio_descriptor *desc); 133 extern void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *, pgoff_t); 134 extern size_t nfs_generic_pg_test(struct nfs_pageio_descriptor *desc, 135 struct nfs_page *prev, 136 struct nfs_page *req); 137 extern int nfs_wait_on_request(struct nfs_page *); 138 extern void nfs_unlock_request(struct nfs_page *req); 139 extern void nfs_unlock_and_release_request(struct nfs_page *); 140 extern int nfs_page_group_lock(struct nfs_page *, bool); 141 extern void nfs_page_group_lock_wait(struct nfs_page *); 142 extern void nfs_page_group_unlock(struct nfs_page *); 143 extern bool nfs_page_group_sync_on_bit(struct nfs_page *, unsigned int); 144 145 /* 146 * Lock the page of an asynchronous request 147 */ 148 static inline int 149 nfs_lock_request(struct nfs_page *req) 150 { 151 return !test_and_set_bit(PG_BUSY, &req->wb_flags); 152 } 153 154 /** 155 * nfs_list_add_request - Insert a request into a list 156 * @req: request 157 * @head: head of list into which to insert the request. 158 */ 159 static inline void 160 nfs_list_add_request(struct nfs_page *req, struct list_head *head) 161 { 162 list_add_tail(&req->wb_list, head); 163 } 164 165 166 /** 167 * nfs_list_remove_request - Remove a request from its wb_list 168 * @req: request 169 */ 170 static inline void 171 nfs_list_remove_request(struct nfs_page *req) 172 { 173 if (list_empty(&req->wb_list)) 174 return; 175 list_del_init(&req->wb_list); 176 } 177 178 static inline struct nfs_page * 179 nfs_list_entry(struct list_head *head) 180 { 181 return list_entry(head, struct nfs_page, wb_list); 182 } 183 184 static inline 185 loff_t req_offset(struct nfs_page *req) 186 { 187 return (((loff_t)req->wb_index) << PAGE_CACHE_SHIFT) + req->wb_offset; 188 } 189 190 #endif /* _LINUX_NFS_PAGE_H */ 191